Electrical apparatus



Oct. 16, 1928. 1,687,868

R. H. LANGLEY ELECTRICAL APPARATUS Original Filed June 10. 1922 2 Sheets-Sheet 1 73 7 Fig. 2.

I. 32 11 '3 24 Inventor: .30 Ralph H. Lan leg,

His Atmor-neg- Oct. 16, 1928. 1,687,868

R. H. LANGLEY ELEGTRI CAL APPARATUS 0riginal Filed June 10. 1922 2 Sheets-sheaf, 2

Inventor: Ralph H. Langlel His Abner-neg Pastel! 0a. 16, 1928.

UNITED STATES OF SCITENECTADY, YORK, ASSIGNOR TO GENERAL ELECTRIC GOMPANY, A CORPORATION OF NEW YORK.

RALPH H. LANGLEY,

ELECTRICAL APPARATUS.

o iginal application filed June 10, 1922,

This invention relates to electrical appara= tus of the type ordinarily referred to as variable air condensers, in connection with which switching'means is provided underthe control of the condenser element.

My invention will be more fully understood from the following specificat on, reference being had to the accompanying drawings wherein Fig. 1 is a plan view of a condenser and switch embodying my invention (the knob for operating the condenser being omitted) Fig. 2 is a central sectional view partly in elevation of the condenser shown in Fig.

1; Fig. 3 is a rear elevation of the structure shown in Fig. 2; Fig. 4 isa fragmentary, per spective view showing the manner in which the stationary and movable plates are supported; 5 is an enlarged detail showing the manner in which the metal members which form the bearing of the condenser are attached to the insulating supporting plates; Fig. 6 is a perspective view of a modified form of condenser plate supporting post;'Fig. 7 is aplan view of a modified form ofc ondenser plate adapted for use with the post shown in Fig. 6; Figs. 8 to 13 inclusive are diagram.

matic views of a circuit-"including thecondenser-and an inductance, the views showing successive positions assumed by the apparatus throughout its entire range of adjustment, and Fig. 14 is a diagrammatic view showing a modified controlling apparatus.

Referring more particularly toFigs. 2 and 4, my condenser is formed of a stator'10 comprising two groups of stationary plates 11 and 12 and arotor 14 comprising two groups of movable plates 15 and 16. The stationary plates are formed of sheets of metal having =circular outer and inner edges these'. edges being formed with notches 17 adapted to cooperate with notches 18 formed at equal distances along supporting posts 19. The posts 19 are secured to an annular supporting memher or plate'2O of insulating material. The

groups of plates 1 1 and 12 are arranged upon opposite sides of a central axis and the angle subtendedby their combined circular periphcry is approximately 320, thus leaving a space of air insulation between the groups of approximately 20 at each side.

The movable groups of plates 15 and 16 are formed of plates which are similarly shaped to thestationarv plates except that their inner and outer diameters aresomewhat less.

allel'and equidistant from one another.

movable plate should be locatedas near as Serial No. 567,323. Divided and this application filed December 1, 1923. Serial No. 152,029.

The inner circular edges of the movable plates are formed with notches 21 adapted to cooperate with notches 22 formed on the supporting metal posts 23. The post-s23 are secured to a circular plate 24' of insulating material. This plate is located inside of the space within and some distance from the annular supporting member 20. I The plate 24 is rotatably supported b means of a ball bearing. This ball bearing is formed of an external metal spider 26" having legs 27 secured by means of inset bolts 28 to the insulating member 20 and an inner metal spider 30 having legs 31 secured to the central plate .24 by inset bolts 32 (see Fig. 5).

The inner spider is formed of a hub portion 33 having a central opening 34 adapted to receive a suitable kn'obor handle (not shown) for rotating the spider. The outer spider 26' is formed with a central opening 35 in the face of which there is formed a groove 36 which constitutes a portion 'of' a ball race. The'balls 38 are held between the faces of the groove 36 and inclined face 39 on the spider 30 and a face 40 formed on a member 41, which member is secured 'to the central portion or hub of the spider 30 by means of a locked nut 42.

It will be noted that the electrical fieldtween the plate 24 and annular member 20 or must pass from the posts 19 to the legs of the outer spider and from thelegs of the inner spider to the posts 23. It is clear that this i latter path is of considerable length and the former while somewhat shorter extends across a substantial air gap. This results in the material reduction in electric losses-Lwhichoccur in the insulation and permits the use of such insulating compound as bakelite which otherwise would be but poorly suited for the purpose.

In the manufacture of condensers of this type the plates of the stator group, as well as those of the rotor, should be maintained arpossible halfway between the stationary,

plates. In many of the condensers heretofore manufactured theplates have been held apart by individual spacers. In certain cases the spacers are threaded on supporting shafts and held apart by rings or washers surround ing the shafts. It is clear that any slight deviationin the thickness of the washers or other spacers will be multiplied when taken over an entire group of plates and the misplacement of certain of the plates may therefore be considerable. Because of slight differences which exist in the thickness of the washers it has been the practice in assembling the condensers to select carefully washers of the proper dimensions for each individual condenser. This method of assembling consumes considerable time and adds to the expense of manufacture. According to my invention I avoid the use of the individual spacers and in other respects provide an im proved and efficient method of construction. In accordance with this method provision is made whereby notches 18 and 22 of all of the posts are cut at one operation. The post blanks are all held in a clamp and the notches are cut by a gang of saws which have themselves been accurately spaced. The end saws of the gang are arranged to project in ad vance of the'remaining saws so as to cut off the ends of the posts to a definite dimension. It is clear that the saws when once set in place in the cutting machine may be used in the manufacture of a great number of condensers and thus the expense due to the time spent in accurately adjusting the saws is distributed. The conducting plates after assembly on the posts are preferably firmly secured thereto by soldering.

In Figs. 6 and 7 I have shown an alternative construction for the support of the conducting plates wherein the posts are formed of a. channel-shaped punching 50 and the plates are formed of sheets which are punched with tongues 51 adapted to be held within slots 52 in the punchings 50 and notches 53 arranged upon opposite sides of the tongues 51, which notches cooperate with notches 54 in the punching 50. After assembly the plates are soldered to the posts as in the former case. I i

In order to provide for strict parallelism of the interleaved plates and also for the main tenance at all times of a proper distance between the same, the inner faces of the member 20 and theplate 24 from which the posts 19 and 23 extend are formed so as to lie in a single plane and the groove 36 of the ball A race 37 is so formed that the balls 38 will 8 as a drop-forging or casting, after being drilled and tapped is secured 1n. a chuck and the outer face 56 of the spider and the groove 36 are formed in one operation so that the plane of the outer face 56and that of the center of the groove 36 are parallel. The

' two spiders are then assembled with the balls 38 and the member 41 in place and the entire structurebolted to a face plate with the face 56 bearing against the plate. The. face plate is provided with suitable means for prevent ing the relative rotation of thetwo spiders. The faces of the feet ofboth spiders are then turned oif to a single plane and are drilled and tapped as shown and secured to their corresponding members 20 and 24. A light cut is then taken across the inner faces of the plate 24 and member 20 so as to cause these two faces to lie in a common plane. The groups of rotor and stator plates are then assembled and the posts 23 are bolted to plate 20 by bolts 59 which may be inserted through opening 60 formed in the spider 39 and member 41. i

To the free ends of the posts 23 an arcuate conducting member or contact 61 and a similar member or contact 62 are secured. Secured to oppositely located posts there are provided brushes 63 and 64 which are arranged to bear against the conducting members 61 and 62 in the manner shown (see Fig. 4). By this means, and upon the movement of the rotor 14 and the contacts 61 and 62 certain circuit relations are established between the groups of plates which will be more fully described.

Secured to the insulating member 20 and operable from the rotor 14 is a switch 7 0 which comprises a stationary contact 71 mounted upon an insulating plate 72 which is also secured to the annular member 20. A movable contact 73 is pivoted at the point 74 and is biased by means of a spring 75 connected at one end to the contact and at the other end to the spider 26 to either. open or closed position, depending upon which side of the dead center the spring 75 is acting. The inner end of the plate 72 forms a stop for the contact 73 in its open position. If desired, the spring 75 may be supported at its inner ends in such a manner as to be insulated from the metal spider 26.

The pivoted contact 73 is formed with a bifurcated inner end 7 6 which is adapted to cooperate with a lug 7 7 carried by the rotary plate 24 to move the switch in-one direction or the other. A similar lug 77 is fixed to the plate 24 at a point diametrically opposite the first lug. This second lug is adapted to engage the inner end 76 of the contact 73 at one side or the'other to arrest the motion of the rotor in either direction.

In Figs. 8 to 13 inclusive I show diagrammatically a radio receiving circuit employing the condenser and switch above described. The groups of the plates of the condenser in these figures are each represented by circular lines for convenience in illustration. In these figures, 80 represents an antenna, 81 an inductance, which as shown is grounded at one end, and is formed of two portions 83 and 84. the portion 84 being grounded and the por tion 83 connected to one ofthe br'ushes 63 or 64 of the condenser; the antenna 80 is connected to the opposite brush; a tap 85 extends from-thepoint at which the sections 83 and 84 of the inductance join, to the switch arm 73. Thestationary contact 71 of the i should be reversed and the movable contact 73 connected to the ground and the stationary contact 71 to the tap 85 because it has been found generally advisable to ground the metal bearing of the condenser.

The values of inductance and capacity tobe used are so chosen that the desired wave length range will be obtained. The portion 83 of inductance must be such as to give the desired minimum wave length with the'chosen antenna and with the condenser in minimum position. This value of inductance willgive a larger wave length when the condenser is in maximum position. The portions 83 and 84 connected in series must be such as to give.

awave length somewhat lower than the wave length last above mentioned with the condenser in minimum position and a desiredmaximum wave length with the condenser in maximum position.

It will be noted that in Fig. 8 the condenser is in the position of minimum capacity, the group of plates 11 and Iii-being connected through the brush 64 and the group of plates 12 and 16 being connected through the brush 63. The capacity of the condenser in this 1 position is merely that which exists between that it is closed for the first 180.

the two masses of metal comprising the groups 11 and 14 on the one hand and the groups'12- and 16 on the other.

In Figs. 8 to 13 the rotors are so arranged as to have the capacity increase with clockwise rotation. The contact brushes 63 and 64 are so arranged that when the rotors have turned to the maximum capacity position, a

slight further rotation will reverse the. connection so as to return the condenser to its minimum capacity. When the rotation is I again continued in the same direction the condenser again increases in capacity to its maximum value. The switch 70 is arranged so This means that the portion 84 of the inductance 81 is lower wave. length range.

viewed in Fig. 1 is opened counterclockwise short circuited for the first 180, giving the The switch as and closed clockwise by thelug 77.

Fig. 8 shows the circuit at the minimum wave length adjustment. The switch is closed and only. the portion 830i the inductance is in 'circuit. The capacity is a minimum. Rotation of the movable groups of plates in the counterclockwise direction is prevented by engagement of the lug 77 with the inner end of switch arm 75.

Fig. 9 shows an adjustment'of the con-- length range at about 170" The groups 15 and 16 have advanced clockwise into complete mesh with the groups of opposite polarity. It is to be noted that within the next few degrees of rotation the lug 7 7 will strike the switch arm and open the switch. It will also be seen that the brushes 63 and 64 will then make contact with the groups 15 and 16 respectively, instead of with 16 and 15 respectively, thus returning the condenser to its minimum capacity position.

Fig. 11 shows the be inning of the higher wave length range with the rotor displaced from the position shown in Fig.8 by approximately 190. Because of the change just made in the connections through the brushes, the capacity of the condenser is at a minimum, the switch 70' has been opened andthe entire inductance 81 is now in circuit.

In Fig. 12 is shown the middle position of the higher wave length atabout 270. The rotor groups have again advanced into partial mesh with the stator groups of opposite polarity and the capacity is again increased to approximately 50% of its maximum value.

In Fig. 13. the final position giving the maximum wave length is shown wherein the rotor is displaced from the position shown in wise direction.

It will be noted that upon the reversed movement of the rotor from the position shown in Fig. 13, thecycle will take in a reverse order from that previously described.

Fig. 14 I have shown an arrangement which permits a still greater variation of wave length without increasing the capacity of the condenser. In this figure the inductance 86 is divided into three groups, 87, 88 and 89, and two switches are provided, 90 and 91, whereby one or both groups may be short circuited; The rotor of the condenser is provided with but onelug 77 instead of the two employed in the apparatus.above de-- scribed. As in the previous case the switches may be moved by the lug in one direction but of the lug upon the same coming in contact with switch arm when moving in the opposite direct on. It will be noted that with the use they will serve as a stop to prevent movement of a single lug it is possible to rotate the movable groups of the condenser through 540,

thereby causing the condenser to move from.

its minimum to its maximum position three times. WVith both the switches closed, which is their position at starting, as shown in Fig. 14, both portions 88' and 89 of the inductance 86 are short circuited. After 180 of clockwise rotation, lug 77 opens switch 90, putting the section 88 of the inductance in circuit and after 360 of rotation, the lug 77 opens switch 91, putting the entire inductance into circuit. At 540 the lug strikes the inner end of the arm of the switch 90, thus preventing further movement in that direction. It will also be seen that upon the reversed movement this entire cycle is reversed. i

If more than three ranges of wave length are required it is possible to arrange multiple throw switches, the movable arms of which are formed with pins which are adapted to ride in a groove formed in a rotary cam. The groove consists of several 160 circular ortions at increasing radii and connected at t eir ends by 20 cross-over grooves. The circular portions are adapted to hold the switch stationary while the rotor is being turned. The cross-over portions carry the pin on the arm of the switch from one groove to the next and consequently move the switch from one contact to the adjacent contact. This occurs while the rotors are changing their connections by means of the brushes 63""and 64 to change the condenser from its maximum to its minimum position or vice versa.

lVhat I claim as newand desire to secure by Letters Patent of the United States, is,

1. In an adjustable condenser, a stator element comprising a stator plate and a rotor element comprising a rotor plate and a switch having one of its elements connected to the stator plate and another one of its elements connected to the rotor plate, said switch being under the control of the rotor element and operable thereby whereby the rotor and stator plates may be connected and disconnected.

2. An adjustable condenser comprising a rotor "element and a stator element, one of said elements having a plate and the other having a pair of plates and a switch having a separate element connected to each of said plates, said switch being under the control of the rotor element and operable thereby whereby one of said plates may be connected with either one of the remaining plates.

3. In an adjustable condenser, a supporting frame, a stator, said stator, having two sections and having a plate in each section, said plates being disposed transverse the axis of the condenser, one of said plates being located on one side of a plane through the axis of the condenser and the other plate on the opposite side of said plane, both plates being supported by said frame and insulated from each other, a rotor for said condenser, said rotor having two sections and having a plate in each section, said plates being disposed transverse the axis of'the condenser and located in inductive relation to said stator, one of said rotor plates being located on one side of a plane through the axis of the rotor and the other of the rotor plates being located on the opposite side of the said plane through said rotor axis and insulated from each other, a commutator device comprising segment elements and brush elements for interconnecting each section of the rotor alternately with each section of the stator, one segment element being-connected to and mounted on each rotor section to rotate therewith and one brush element being mounted stationary on and connected to each stator section, whereby either rotor section may be connected with either stator section, and a switch mounted on said condenser under operative control of the rotor whereby the switch may be opened or closed by the rotor, the relation of the switch to the condenser being such that either section of the rotor may be connected with either section of the stator, while the switch is opened or while the switch is closed.

In witness whereof, I have hereunto set my hand this 27th day of November, 1926.

RALPH H. LANGLEY. 

